<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>05-ajax-get-ie兼容</title>

    <script>
      window.onload = function (ev) {
        var oBtn = document.querySelector("button");
        oBtn.onclick = function (ev1) {
          var xhr;
          if (window.XMLHttpRequest) {
            // code for IE7+, Firefox, Chrome, Opera, Safari
            xhr = new XMLHttpRequest();
          } else {
            // code for IE6, IE5
            xhr = new ActiveXObject("Microsoft.XMLHTTP");
          }
          // var xhr = new XMLHttpRequest();
          /*
                在IE浏览器中, 如果通过Ajax发送GET请求, 那么IE浏览器认为
                同一个URL只有一个结果
                05-ajax-get.txt === abc

                console.log(Math.random());
                console.log(new Date().getTime());
                */
          xhr.open("GET", "05-ajax-get-ie.txt?t=" + new Date().getTime(), true);
          xhr.send();
          xhr.onreadystatechange = function (ev2) {
            if (xhr.readyState === 4) {
              if (
                (xhr.status >= 200 && xhr.status < 300) ||
                xhr.status === 304
              ) {
                // alert("请求成功");
                alert(xhr.responseText);
              } else {
                alert("请求失败");
              }
            }
          };
        };
      };
    </script>
  </head>
  <body>
    <button>发送请求</button>
  </body>
</html>
